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Atomic layer deposition as a tool for tailoring adhesion properties of interfaces. |
Matti Putkonen 1, Timo Sajavaara 2, Paavo Rahkila 3, Harry J. Whitlow 2, Sulin Cheng 3, Lauri Niinisto 4, Mikko Saloniemi 5,7, Mauno Könönen 5,6, Jorma Kivilahti 7, Tommi Kääriäinen 8, Mari Tanttari 8, David Cameron 8 |
1. Beneq Oy, Ensimmainen Savu, Vantaa 01510, Finland |
Abstract |
Adhesion properties of inorganic-biological and inorganic-inorganic interfaces play an important role in modern technology applications. ALD is a unique method due to its controllability even at nanometer scale level. We will present results from three different material combinations where surface properties were altered by ALD. Ca-P-O mimicking hydroxyapatite (Ca10(PO4)6(OH)2) were deposited onto silicon, glass or sapphire substrates. The phosphorus content was controlled by changing the pulsing ratio between Ca(thd)2/O3 and (CH3O)3PO/H2O. Ca-P-O films were crystallized at 500-800 oC by RTA treatment in a moist N2 atmosphere. According to the bioactivity test carried out by mouse pre-osteoblast MC-3T3-cells it was observed that stoichiometric and crystallized films enhanced the profileration and adhesion of cells at the surface. TiCl4/H2O and ZrCl4/H2O processes were utilized for the deposition of TiO2 and ZrO2 films onto titanium substrates for tailoring metalloceramic interface layers of dental applications. After thin film deposition, commercial dental porcelain (DuceratinPlus) was applied and fired at 780 ºC. Three-point bending tests were executed according to DIN 13927. It was observed that a thin oxide layer restrains the reactions between silicon based ceramics and metallic titanium to inhibit formation of a weak silicide layer. TiO2 and Al2O3 thin films were used for improving the adhesion between sputtered Ti or TiC and polymeric PMMA or PC substrates. Tetrakisdimethylamidotitanium (TDMAT) and TMA were used as metal precursors and ozone as an oxygen source. As the ALD film thickness was increased there was a significant effect on the adhesion properties. The most prominent increase in adhesion was obtained by a 30-50 nm thick layer between PMMA and TiC and with optimal film thickness the adhesion force exceeded the cohesion force of the polymeric substrate and led to disruption deep within the bulk of the polymer, not between the substrate and coating. |
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Presentation: Oral at E-MRS Fall Meeting 2007, Symposium C, by Matti PutkonenSee On-line Journal of E-MRS Fall Meeting 2007 Submitted: 2007-05-14 12:02 Revised: 2009-06-07 00:44 |